import math

if __name__ == '__main__':
    res = []
    while True:
        inp = input()
        if not inp:
            break
        n, m = map(int, inp.split())
        a = 0
        for i in range(m):
            a += n
            n = math.sqrt(n)
        res.append('{:.2f}'.format(a))

    for i in range(len(res)):
        print(res[i])
